Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C67/00—Preparation of carboxylic acid esters
  • C07C67/30—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group
  • C07C67/333—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group by isomerisation; by change of size of the carbon skeleton
  • C07C67/343—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group by isomerisation; by change of size of the carbon skeleton by increase in the number of carbon atoms
  • C07C67/347—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group by isomerisation; by change of size of the carbon skeleton by increase in the number of carbon atoms by addition to unsaturated carbon-to-carbon bonds
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
  • C07C51/09—Preparation of carboxylic acids or their salts, halides or anhydrides from carboxylic acid esters or lactones
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C67/00—Preparation of carboxylic acid esters
  • C07C67/39—Preparation of carboxylic acid esters by oxidation of groups which are precursors for the acid moiety of the ester

Definitions

• adipic acid In the production of adipic acid by hydroesterification of pentenoic acid esters, considerable amounts of 2-methylglutaric acid esters and 3-ethylsuccinic acid esters are obtained as a by-product. Thus, adipic acid is only obtained from a fraction of the pentenoic acid ester used.
• the new process has the advantage that adipic acid is obtained starting from pentenoic esters, while avoiding undesired isomers.
• the new process also has the advantage that the accumulation of other by-products and cyclic compounds is minimized.
• pentenoic esters are hydroformylated.
• Suitable pentenoic esters are derived from alkanols with 1 to 12 carbon atoms or cycloalkanols with 5 to 8 carbon atoms.
• Suitable compounds are e.g. 4-pentenoate, 3-pentenoate and 2-pentenoate individually or mixtures thereof.
• Examples include methyl, ethyl, propyl, isopropyl, butyl, hexyl, nonyl, dodecyl, cyclopentyl or cyclohexyl esters of 2-, 3- or 4-pentenoic acid.
• the hydroformylation of the pentenoic acid ester is carried out at elevated temperature, advantageously at a temperature of 60 to 160 ° C., in particular from 80 to 120 ° C.
• an increased pressure is maintained, advantageously from 5 to 300 bar.
• the pentenoic acid esters are hydroformylated by reaction with carbon monoxide and hydrogen.
• the gas mixture contains carbon monoxide and hydrogen in a molar ratio of 1: 0.5 to 1:10, in particular 1: 1 to 1: 2.
• the hydroformylation is carried out in the presence of cobalt or rhodium carbonyl complexes.
• the carbonyl complexes can be prepared from cobalt or rhodium salts by reaction with carbon monoxide before the reaction. They are advantageously formed in situ from the salts of rhodium or cobalt.
• the cobalt or rhodium carbonyl complexes used are preferably additionally modified by tertiary phosphines or tertiary phosphites. Suitable phosphines or phosphites have alkyl radicals with up to 12 carbon atoms and / or phenyl radicals which can additionally contain alkyl groups with up to 4 carbon atoms as substituents.
• Triphenylphosphine substituted triarylphosphines such as tritolylphosphine, and also alkyldiarylphosphines such as hexyldiphenylphosphine are preferably used.
• cobalt carbonyl complexes it has proven useful if 0.01 to 1 mol%, preferably 0.05 to 0.3 mol%, in particular 0.08 to 0.25 mol%, of cobalt carbonyl complexes, calculated as cobalt, based on the amount used Pentenic acid ester applies. It is also advantageous to maintain a conversion of the pentenoic esters used of 10 to 50%, in particular 20 to 40%. This reduces the formation of by-products by hydrogenation and aldolization. Under these conditions, it is possible to dispense with the use of solvents and to use cobalt carbonyl complexes which contain up to 20 moles per mole of cobalt of tertiary nitrogen bases without the hydroformylation being adversely affected. Such catalysts fall e.g. in the hydroesterification of butadiene to pentenoic acid ester, as described in European Patent 31,100.
• solvents which are inert under the reaction conditions.
• Suitable solvents are, for example, ethers such as tetrahydrofuran, carboxylic acid esters such as valeric acid ester, butyric acid ester or acetic acid ester and hydrocarbons such as toluene.
• the removal of the cobalt catalyst is complete after only a few seconds or fractions of a second.
• the aqueous phase containing cobalt is expediently separated off by decanting.
• the organic phase obtained is a mixture of 5-, 4- and 3-formylvalerate esters which also contains high boilers and valerate esters as well as unreacted pentenoate esters and, if appropriate, solvents.
• the mixture of formylvaleric esters freed from the catalyst is separated by distillation.
• any solvent which is also used and unconverted pentenoate esters are first separated off individually or as a mixture and this is expediently returned to the hydroformylation stage.
• step b) 5-formylvaleric acid ester is separated from the mixture thus obtained 5-, 4- and 3-formylvaleric acid ester and possibly small amounts of high boilers by distillation, leaving a mixture consisting essentially of 4- and 3-formylvaleric acid esters.
• small amounts e.g. up to 5% by weight of 5-formylvalerate can be contained.
• step c) the mixture thus obtained, which essentially consists of 4- and 3-formylvaleric acid esters, is formed to form pentenoic acid esters at a temperature of 50 to 400 ° C. in the presence of at least one element of the 8th subgroup of the periodic system dehydrocarbonylated and the pentenoate obtained in step a) for hydroformylation.
• the pure 4- and 3-formylvaleric esters can be used for the process according to the invention, it is generally expedient to use their mixtures, which, depending on the efficiency of the distillation, may also contain 5-formylvaleric esters.
• a typical mixture contains, for example, 60 to 75% by weight of 4-formylvalerate, 25 to 35% by weight of 3-formylvalerate and up to 5% by weight of 5-formylvalerate.
• 4-, 3- and 2-pentenoate esters, predominantly 3-pentenoate esters, are obtained as dehydrocarbonylation products.
• Suitable homogeneous catalysts are complex compounds of noble metals of subgroup 8 of the periodic system, in particular of ruthenium or rhodium.
• Halogens such as chlorine or bromine and phosphine or phosphite-containing ruthenium or rhodium complexes which can additionally contain carbon monoxide as ligands are particularly suitable.
• Tertiary organic phosphines or phosphites are particularly preferably used as modifiers.
• Such phosphines or phosphites preferably have as substituents alkyl radicals with up to 18 carbon atoms, cycloalkyl radicals with 5 to 12 carbon atoms, aralkyl radicals with 7 to 10 carbon atoms or aryl radicals with 6 to 10 carbon atoms, in particular phenyl radicals.
• the residues can be the same or different.
• suitable complex compounds are RhCl [P (C6H5) 3] 3, Ru2Cl3 [P (C6H5) (C2H5) 2) 6] Cl, RhBr (CO) [P (C6H5) 3] 2, HRuCl (CO) [P ( C6H5) 2] 3, RhCl (CO) [P (C6H5) 3] 2.
• Supported catalysts are preferably used which contain at least one of the elements of subgroup 8 of the periodic system, such as palladium, platinum, ruthenium, rhodium, osmium, iridium, iron, cobalt or nickel, but especially noble metals of this group.
• Supported catalysts which contain at least two noble metals from subgroup 8 of the periodic system, such as ruthenium, rhodium, palladium or platinum are also advantageous.
• Other preferred catalysts contain at least one metal of the aforementioned noble metals from subgroup 8 of the periodic system and additionally at least one metal selected from the group consisting of iron, cobalt and nickel.
• the supported catalysts advantageously have an active metal content of subgroup 8 of the periodic system of 0.01 to 10, preferably 0.05 to 5, in particular 0.05 to 1% by weight, based on the sum of the support and catalytically active metals , calculated as metals.
• Aluminum oxide, silicon dioxide, titanium dioxide, zirconium dioxide, zinc oxide, Lauthan oxide, barium sulfate or mixtures of these oxides and aluminum silicates are advantageously used as carriers.
• Impregnation catalysts in which the catalytically active metals are enriched on the surface of the support.
• Such catalysts are prepared in a manner known per se by impregnating deformed supports such as pellets, spheres or strands with an aqueous solution of the metal salts which, when heated, change to their oxides, e.g. receive the nitrates, which can then be dried, calcined and used directly or optionally after reduction with hydrogen or other reducing agents.
• the catalysts used in stage c) show high activity over a longer period of time.
• Used catalysts can be treated by treatment with gases containing oxygen, e.g. Regenerate air at a temperature of 350 to 500 ° C and, if necessary, subsequent reduction.
• gases containing oxygen e.g. Regenerate air at a temperature of 350 to 500 ° C and, if necessary, subsequent reduction.
• the cleavage is carried out under atmospheric pressure. However, it is also possible to use reduced pressure or increased pressure, advantageously in the range from 10 mbar to 20 bar.
• a catalyst load of 0.01 to 40, preferably 0.1 to 20 kg of formylvaleric acid ester per kg of catalyst per hour is observed.
• the dehydrocarbonylation in stage c) is advantageously carried out using molecular oxygen or gases containing molecular oxygen which, in addition to oxygen, contain inert gases such as nitrogen, carbon dioxide, argon or water vapor, for example air.
• molecular oxygen or gases containing molecular oxygen which, in addition to oxygen, contain inert gases such as nitrogen, carbon dioxide, argon or water vapor, for example air.
• Suitable diluents are e.g. Water, alcohols such as methanol, ethanol, butanol or cyclohexanol, furthermore ethers, such as dioxane or tetrahydrofuran, and chlorinated hydrocarbons, such as methylene chloride, chloroform or 1,2-dichloromethane.
• aliphatic, cycloaliphatic or aromatic hydrocarbons such as benzene, toluene, cyclohexane or paraffins, in addition esters such as acetic acid ester or propionic acid ester.
• esters such as acetic acid ester or propionic acid ester.
• the alcohol which corresponds to the alcohol bound in the formylvaleric esters is advantageously used.
• the starting material and product can thus be easily separated by distillation by means of a sufficient boiling point difference. It has proven useful if the molar ratio of formylvaleric acid esters to diluents is from 1: 0.1 to 1:50, in particular from 1: 0.5 to 1:20.
• Particularly preferred diluents are water and alkanols with 1 to 6 carbon atoms, especially methanol.
• the dehydrocarbonylation in stage c) can be carried out discontinuously or continuously as a fixed bed reaction with fixed bed catalysts, for example in the bottom or trickle phase in the liquid or gas phase or as a fluidized bed reaction with catalysts in the gas phase, and furthermore in the liquid phase with soluble ones Catalysts or suspended supported catalysts are carried out.
• a preferred embodiment in stage c) in the liquid phase is carried out, for example, by passing formylvaleric acid esters and optionally diluents with oxygen-containing gases over a solid catalyst at a temperature below the boiling point of the formylvaleric acid ester or in the presence of a suspended solid catalyst or a dissolved homogeneous catalyst heated.
• the liquid reaction product obtained is then separated after separation of the catalysts by distillation in pentenoate and optionally diluent and unreacted formylvalerate.
• stage c) in the gas phase is carried out, for example, by evaporating a mixture of formylvaleric acid ester and, if appropriate, diluent and then gaseous together with air, advantageously with additional carrier gas, such as nitrogen-carbon dioxide or argon, at the temperatures indicated initiates a fixed catalyst layer or a catalyst layer which is in a swirling and swirling motion.
• additional carrier gas such as nitrogen-carbon dioxide or argon
• step d) the 5-formylvaleric acid esters obtained in step b) are oxidized to adipic acid monoesters with molecular oxygen or gases containing them.
• the oxidation is advantageously carried out at a temperature of 20 to 100 ° C., in particular 50 to 97 ° C. and under a pressure of 1 to 10 bar.
• the molecular oxygen-containing gases can e.g. contain up to 80 vol.% Inert such as nitrogen, carbon dioxide or noble gases.
• the oxidation usually takes place without a catalyst. But it can also by adding catalysts such as alkali hydroxides, e.g.
• Potassium hydroxide or sodium hydroxide in amounts of 0.001 to 0.5% by weight or metal salts of cobalt or manganese e.g. Cobalt acetate or manganese acetate in amounts of 0.001 to 0.1% by weight, preferably 0.02 to 0.08% by weight, calculated as metal, can also be accelerated.
• Cobalt acetate or manganese acetate in amounts of 0.001 to 0.1% by weight, preferably 0.02 to 0.08% by weight, calculated as metal can also be accelerated.
• Purely adipic acid monoesters are expediently obtained from the reaction mixture by distillation.
• step e) the adipic acid monoesters thus obtained are hydrolyzed to adipic acid. It is advantageous to use 1 to 200 mol, in particular 50 to 150 mol, of water per mol of adipic acid monoester.
• solvents which are inert under the reaction conditions can also be used. Suitable solvents are, for example, hydrocarbons such as cyclohexane or toluene, furthermore halogenated hydrocarbons such as dichloromethane or carbon tetrachloride, furthermore ethers such as dioxane or diglycine. If solvents are used, the adipic acid monoesters are used as a 1 to 90% by weight solution, in particular a 5 to 20% by weight solution, advantageously as an aqueous solution.
• the hydrolysis is advantageously carried out at a temperature of 30 to 200 ° C. A temperature of 50 to 120 ° C is advantageously used. In general, atmospheric pressure is maintained. However, it is also possible to use slightly reduced pressure or slightly increased pressure, e.g. use up to 20 bar.
• Suitable acidic agents are, for example, sulfonic acids, Lewis acids, non-oxidizing mineral acids, lower fatty acids or strongly acidic cation exchangers.
• Suitable acidic agents are, for example, non-oxidizing mineral acids, such as sulfuric acid, hydrochloric acid, hydrobromic acid, and also sulfonic acid, such as p-toluene sulfonic acid or Lewis acids, such as zinc chloride, in addition lower aliphatic carboxylic acids such as formic acid, acetic acid or propionic acid and oxalic acid, and also strongly acidic ion exchangers which are built up, for example, from crosslinked polystyrene with sulfonic acid groups or phenolic resins with sulfonic groups, and also acidic zeolites.
• Acids are advantageously used for the hydrolysis in homogeneous phase in catalytic amounts, for example from 0.002 to 0.25 mol / mol of adipic acid monoester.
• Aliphatic carboxylic acids are generally used in amounts of 0.1 to 1 mol / mol of adipic acid monoester.
• Strongly acidic cation exchangers are particularly preferably used.
• Adipic acid which can be obtained by the process according to the invention, is an important starting material for the production of polyamides.

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• 1987
  • 1987-06-15 DE DE19873719936 patent/DE3719936A1/de not_active Withdrawn
• 1988
  • 1988-06-08 EP EP88109088A patent/EP0295551B1/fr not_active Expired - Lifetime
  • 1988-06-08 DE DE8888109088T patent/DE3880208D1/de not_active Expired - Fee Related
  • 1988-06-08 ES ES88109088T patent/ES2042647T3/es not_active Expired - Lifetime
  • 1988-06-10 US US07/205,340 patent/US4931590A/en not_active Expired - Lifetime
  • 1988-06-15 JP JP63145974A patent/JP2585721B2/ja not_active Expired - Fee Related

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